From Bugzilla Helper:
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 4.0)
Description of problem:
rcp, as derived from the netkit-rsh-0.17 source in Red Hat 7.x, doesn't handle
files larger than 2GB. There are two types of failure:
- an existing large file can't be opened by rcp (the open() call fails with
EFBIG)
- trying to write a file on a Red Hat system that the remote side claims is
larger than 2GB will result in the size variable in sink(), which is declared
as an int, not to reflect the actual size of the file (it might be negative, or
it might be filesize%4GB, because of the overflow) and the copy will be aborted
prematurely after the Red Hat system's rcp believes it has read in the correct
number of bytes.
Fix:
more recent versions of freebsd's rcp fix the C code. The snprintf expression
involving stb.st_size should cast it to (long long) and use %lld instead of %
ld. size should be declared as off_t rather than int. And appropriate CFLAGS
should be defined in the Makefile so that 64-bit versions of off_t, open(), and
stat() get used; I happened to fix this by adding "CFLAGS += -
D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64" to the Makefile.
Version-Release number of selected component (if applicable):
How reproducible:
Always
Steps to Reproduce:
1. rcp largefile remote:destfile
2. (from another system whose rcp supports large files) rcp largefile
redhatsystem:destfile
3.
Additional info:

This is still present in phoebe/rawhide and RHL 8.0 as well. Adding this to the
MCONFIG-editing part and patching it as described by mp above fixes it for me:
s,-O2,\$(RPM_OPT_FLAGS) -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64,;